Identification of sewage markers for the quantification of the severity of rainfall derived infiltration and inflow

Abstract

To assess the feasibility of this alternative to flow measurement in rainfall derived infiltration and inflow (RDII) determination and subsequent sewer condition assessment, it is necessary to first determine if markers are a suitable alternative to direct flow measurement, and which markers are the most capable of doing so. To accomplish this, the objectives are outlined here. 1) Determine suitable markers to characterize dryweather flux. For this, it is important that the chosen markers be predictable and quantifiable. Dry weather flux will become baseline values and be used to calculate the relative amount of I/I under wet weather conditions. Any markers that do not meet the stable flux requirement will not be used. 2) Measure chosen markers and flow during dry and wet weather. 3) Use the chosen markers to determine RI/I. The difference in concentration and flow between dry and wet weather will be used to determine if the mathematical model presented earlier holds true. From these measurements, it will be possible to compare I/I ratios obtained by flow and those obtained from marker measurement. 4) Determine which markers are most suitable to detect relative levels of I/I in sewer systems.